Warming bringing big changes to forests

The compilation of more than 1,000 scientific studies is part of the National Climate Assessment and will serve as a roadmap for managing national forests across the country in coming years. It says the area burned by wildfires is expected to at least double over the next 25 years.

Dave Cleaves, climate adviser to the chief of the U.S. Forest Service, said climate change has become the primary driver for managing national forests, because it poses a major threat to their ability to store carbon and provide clean water and wildlife habitat.

The federal government has spent about $1 billion a year in recent years combating wildfires. Last year was the warmest on record in the lower 48 states and saw 9.2 million acres burned, the third highest on record, according to the National Oceanic and Atmospheric Administration's website.

Insect infestations widely blamed on warming temperatures have killed tens of millions of acres of trees. Forest Service scientist James Vose, the report's lead author, said the research team found that past predictions about how forests will react to climate change largely have come true, increasing their confidence in the current report's predictions.

Along with more fires and insect infestations, forests will see more flooding, erosion and sediment going into streams, where it chokes fish habitat. More rain than snow will fall in the mountains, shortening ski seasons but lengthening hiking seasons. More droughts will make wildfires, insect infestations, and the spread of invasive species even worse.

Beverly Law, professor of global change forest science at Oregon State University, said in an email that her research in Oregon showed that despite more fire, the amount of carbon stored in forests continues to increase.

Tara Hudiburg, a postdoctoral researcher at the University of Illinois, said there is little conclusive evidence that burning trees for bioenergy helps reduce overall carbon emissions. The report did not specifically address whether logging would decrease due to more thinning projects generated by global warming concerns.